Archives de catégorie : biology+acidification

How deep-ocean vents fuel massive phytoplankton blooms

by Stanford’s School of Earth, Energy & Environmental Sciences, June 5, 2019 in WUWT


More “settled science” of the carbon cycle~ctm

Stanford study shows how hydrothermal vents fuel massive phytoplankton blooms — and possible hotspots for carbon storage

Researchers at Stanford University say they have found an aquatic highway that lets nutrients from Earth’s belly sweep up to surface waters off the coast of Antarctica and stimulate explosive growth of microscopic ocean algae.

Their study, published June 5 in the journal Nature Communications, suggests that hydrothermal vents – openings in the seafloor that gush scorching hot streams of mineral-rich fluid – may affect life near the ocean’s surface and the global carbon cycle more than previously thought.

Mathieu Ardyna, a postdoctoral scholar and the study’s lead author, said the research provides the first observed evidence of iron from the Southern Ocean’s depths turning normally anemic surface waters into hotspots for phytoplankton – the tiny algae that sustain the marine food web, pull heat-trapping carbon dioxide out of the air and produce a huge amount of the oxygen we breathe. “Our study shows that iron from hydrothermal vents can well up, travel across hundreds of miles of open ocean and allow phytoplankton to thrive in some very unexpected places,” he said.

Kevin Arrigo, a professor of Earth system science and senior author of the paper, called the findings “important because they show how intimately linked the deep ocean and surface ocean can be.”

Des coraux qui s’adaptent aux températures plus élevées

by Paul Berth, 31 mai 2019 in ScienceClimatEnergie


Selon certaines prédictions, basées sur des modèles informatiques, de nombreux récifs coralliens auront disparu des océans tropicaux au cours des 80 prochaines années[1]. La cause est bien évidemment le réchauffement climatique pouvant provoquer un blanchiment des coraux. Par exemple, en 2014–2017, a eu lieu un évènement global de blanchiment, le 3e au cours des 20 dernières années, et de nombreux coraux furent affectés sur des milliers de kilomètres carrés[2],[3]. Les médias, avides de catastrophisme, en ont beaucoup parlé avec des titres une fois de plus très alarmistes (exemple ici).

Cependant, les choses ne sont pas si simples. Des données satellitaires et des études de terrain ont montré que tous les récifs coralliens ne se comportent pas de la même manière: de nombreux récifs n’ont pas blanchi pendant le dernier épisode El Niño, une très grande partie des coraux a résisté au stress thermique, et de fortes variations locales et régionales ont été observées dans le blanchiment[4]. La relation entre température élevée de l’eau de mer et blanchiment des coraux n’est donc pas évidente. Afin d’éclaircir la situation une équipe américaine a récemment publié une analyse globale des évènements de stress thermique en considérant 3351 sites différents dans 81 pays (Sully et al. 2019, dans Nature Communications[5]). Cette analyse globale est unique et démontre que les coraux sont en train de s’adapter par sélection naturelle et sont désormais un peu plus résistants au blanchiment. Nous avons ici une belle démonstration du fait que les modèles informatiques sont parfois bien loin de la réalité de terrain et qu’il ne faut pas tirer de  conclusions toujours hâtives!

CO2 and ocean chemistry

by Dr. Daniela Mazza, May 18, 2019 in WUWT


Oceans cover about 71% of the earth surface, but their influence on climate change is not only due to high heat capacity of water , not only to the ocean’s water circulation, but to a fact which is widely underestimated : the pH (acidity level) of sea-water is substantially alkaline, ranging from 8.0 to 8.7 . This means that the balance between positive and negative ions is reached by accounting for OH,hydroxide ions, in a far larger amount in respect to H+ hydrogen ions.

The pH value higher than 7 allows seawater to dissolve and react huge amounts of CO2 , carbon dioxide, thus affecting the amount of this gas in the atmosphere by absorbing excess of it. To calculate this excess in respect to what would be the true equilibrium value in the air, all of the chemical reactions involved have to be simultaneously computed, accounting for their equilibrium constants, which in turn depend on temperature.

1 – CO2 (gas) + H2O <==> H2CO3* (H2CO3* is the sum of dissolved CO2 and H2CO3)

2 – H2CO3 <==> H+ + HCO3

3 – HCO3 <==> H+ + CO3– –

4 – H2O <==> H+ + OH

5 – Ca++ + CO3– – <==> CaCO3 (calcite)

6 – Ca++ + OH <==> Ca(OH)+

7 – Mg++ + OH <==> Mg(OH)+

 

Conclusions : CO2 is at 410 ppm far above the equilibrium value (315) , provided a standard seawater composition and an average ocean temperature of 17°C (taken from wikipedia). No doubt that solubility will force more CO2 to be stored in oceans . Moreover if we consider CaCO3 formation (seawater has overshot the solubility of this salt nearly 50 times but nucleation and growth are slow) still more CO2 will be stored by limestone.

Low oxygen levels could temporarily blind marine invertebrates

by Scripps Institution of Oceanography at the University of California San Diego, May 8, 2019 in ScienceDaily


These results, published recently in the Journal of Experimental Biology, are the first demonstration that vision in marine invertebrates is highly sensitive to the amount of available oxygen in the water.

Oxygen levels in the ocean are changing globally from natural and human-induced processes. Many marine invertebrates depend on vision to find food, shelter, and avoid predators, particularly in their early life stages when many are planktonic. This is especially true for crustaceans and cephalopods, which are common prey items for other animals and whose larvae are highly migratory in the water column.

Research on terrestrial animals has shown that low oxygen levels can affect vision. In fact, humans can lose visual function in low oxygen conditions. Pilots flying at high altitude, for instance, have been shown to experience vision impairment if aircraft fail to supplement cockpits with additional oxygen. Additionally, health problems such as high blood pressure and strokes, both associated with oxygen loss, can damage vision.

More Evidence for Rapid Coral Adaptation

by Jim Steele, April 2, 2019 in WUWT


Good news continues to accumulate regards corals’ ability to rapidly adjust to changing climates. The view of coral resilience has been dominated by the narrative of a few scientists. In the 1990s they advocated devastating consequences for coral reefs due to global warming, arguing coral cannot adapt quickly enough. Since the Little Ice Age ended, they believed rising ocean temperatures had brought coral closer to a “bleaching threshold”, a more or less fixed upper temperature limit above which corals cannot survive. Their model predicted the speed of recent global warming “spells catastrophe for tropical marine ecosystems everywhere”. Their assertions that “as much as 95% of the world’s coral may be in danger of being lost by mid-century” was guaranteed to capture headlines and instill public fear. However, a growing body of scientific research increasingly casts doubts on such alarming predictions. Unfortunately, that good news gets much less attention.

A recent peer-reviewed paper titled A Global Analysis of Coral Bleaching Over the Past Two Decades (Sully 2019) compared 20 years of ocean temperatures at which coral bleaching was initiated. From 1998 to 2006, the average sea surface temperature that initiated bleaching was 82.6 °F. But that temperature limit proves not to be “fixed” as earlier researchers incorrectly believed. From 2007 to 2017 the average temperature limit that initiated bleaching was higher, 83.7 °F. This indicates coral have been rapidly adapting to warmer regional climates much faster than once believed.

Global Warming off the hook? Alien species are primary cause of recent global extinctions

by University College London, March 3, 2019 in WUWT


Alien species are the main driver of recent extinctions in both animals and plants, according to a new study by UCL researchers.

They found that since 1500, alien species have been solely responsible for 126 extinctions, 13% of the total number studied.

Of 953 global extinctions, 300 happened in some part because of alien species, and of those 300, 42% had alien species alone listed as the cause of their demise.

The study, published today in Frontiers in Ecology and the Environment, used data from the 2017 IUCN Red List on the total numbers of species that are considered to have gone extinct globally since 1500.

In total, 261 out of 782 animal species (33.4%) and 39 out of 153 plant species (25.5%) listed aliens as one of their extinction drivers. In contrast, native species impacts were associated with only 2.7% of animal extinctions and 4.6% of plant extinctions.

 

 

Coral Reefs in West Hawaiʽi Showing Signs of Recovery

by P. Homewood, February 21, 2019 NotaLotofPeopleKnowThat


Surveys identified 25 coral species in West Hawaiʻi. Lobe coral (Porites lobata), one of the area’s most dominant species, proved to be the most resilient—with only 50% bleaching in 2015. Cauliflower corals (Pocillopora meandrina) were hardest hit—with 98% bleaching—but recent surveys show that they are beginning to recover.

Analysis Finds Oceans Have Become LESS ‘Acidic’ With Rising CO2, Challenging The ‘Acidification’ Narrative

by K. Richard, February 14, 2019 in NoTricksZone


A modest long-term (1800s-present) declining trend in ocean pH values predominantly occurred prior to 1930, or before anthropogenic CO2 emissions began rising precipitously. Since 1930, seawater pH trends have risen slightly, meaning sharply rising CO2 has been coincident with less, not more, ocean “acidification”

 

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Image Source (lower graph): Wei et al., 2015

 

 

GWPF Call For Insect Decline Paper To Be Withdrawn

by P. Homewood, February 11, 2019 in NotaLotofPeopleKnowThat


London, 11 February: The scientific paper behind newspaper claims that insect populations were threatened with extinction was based on data known to be unreliable. That’s according to the Global Warming Policy Foundation, which today called for the paper to be withdrawn.

The paper, by US scientists Bradford C Lister and Andres Garcia, claimed that a rapid decline in insect populations in a rainforest in Puerto Rico was the result of rising temperatures. The Washington Post called the study “hyperalarming”, while the Guardian discussed climate change causing “insect collapse”.

However, the authors’ evidence that temperatures had, in fact, risen turns out to be based on a single weather station, which was known to be unreliable because of undocumented changes to equipment and location resulting in a substantial and abrupt increase in recorded temperatures in September 1992.

Since 1992, temperatures at this station have actually declined.

The Obvious Biomass Emissions Error

by Steve Goreham, February 7, 2019 in WUWT


When Thomas Edison established his Pearl Street power plant in New York City in 1892, he used coal for fuel, not wood. Wood fuel could not compete with the cost of coal in 1892 and it still can’t today. Nevertheless, burning of biomass is widely regarded as sustainable and promoted as a solution for climate change, especially in Europe.

Today, Europe produces about 17 percent of its energy and 29 percent of its electricity from renewable sources. Biomass accounts for about 19 percent of the electricity generated from renewables. Since 2000, Europe’s biomass consumption for energy production is up 84 percent.

For example, biomass fuel produced 18 percent of Denmark’s electricity in 2017. For the last two decades, Denmark has been reducing coal-fired power plant output, but adding biomass-powered plants. Since 2000, Denmark’s use of coal fuel for electricity decreased 63 percent. But the use of biomass fuel for electricity in Denmark increased by a factor of five, almost exactly replacing the decline in coal output. About three-quarters of the biomass consumed by Denmark is wood, with most of it imported.

New islands, happy feet: Study reveals island formation a key driver of penguin speciation

by Molecular Biology and Evolution (Oxford University Press), February 5, 201 in ScienceDaily


Ever since Darwin first set foot on the Galapagos, evolutionary biologists have long known that the geographic isolation of archipelogos has helped spur the formation of new species.

Now, an international research team led by Theresa Cole at the University of Otago, New Zealand, has found the same holds true for penguins. They have found the first compelling evidence that modern penguin diversity is driven by islands, despite spending the majority of their lives at sea.

“We propose that this diversification pulse was tied to the emergence of islands, which created new opportunities for isolation and speciation,” said Cole.

Over the last 5 million years, during the Miocene period, (particularly within the last 2 million years), island emergence in the Southern Hemisphere has driven several branches on the penguin evolutionary tree, and also drove the more recent influence of human-caused extinctions of two recently extinct penguin species from New Zealand’s Chatham Islands.

Study: Much of the surface ocean will shift in color by end of 21st century

by Charles the moderator,  February 5, 2019 in WUWT


Climate-driven changes in phytoplankton communities will intensify the blue and green regions of the world’s oceans

From the Massachusetts Institute of Technology

Climate change is causing significant changes to phytoplankton in the world’s oceans, and a new MIT study finds that over the coming decades these changes will affect the ocean’s color, intensifying its blue regions and its green ones. Satellites should detect these changes in hue, providing early warning of wide-scale changes to marine ecosystems.

Writing in Nature Communications, researchers report that they have developed a global model that simulates the growth and interaction of different species of phytoplankton, or algae, and how the mix of species in various locations will change as temperatures rise around the world. The researchers also simulated the way phytoplankton absorb and reflect light, and how the ocean’s color changes as global warming affects the makeup of phytoplankton communities.

The researchers ran the model through the end of the 21st century and found that, by the year 2100, more than 50 percent of the world’s oceans will shift in color, due to climate change.

Scientists identify two new species of fungi in retreating Arctic glacier

by Research Organization of Information and Systems, January 15, 2019 in ScienceDaily


Two new species of fungi have made an appearance in a rapidly melting glacier on Ellesmere Island in the Canadian Arctic, just west of Greenland. A collaborative team of researchers from Japan’s National Institute of Polar Research, The Graduate University for Advanced Studies in Tokyo, Japan, and Laval University in Québec, Canada made the discovery.

The scientists published their results on DATE in two separate papers, one for each new species, in the International Journal of Systematic and Evolutionary Microbiology.

“The knowledge of fungi inhabiting the Arctic is still fragmentary. We set out to survey the fungal diversity in the Canadian High Arctic,” said Masaharu Tsuji, a project researcher at the National Institute of Polar Research in Japan and first author on both papers. “We found two new fungal species in the same investigation on Ellesmere Island.”

Algae thrive under Greenland sea ice

by Bigelow Laboratory for Ocean Sciences, January 8, 2019 in ScicneDaily


Microscopic marine plants flourish beneath the ice that covers the Greenland Sea, according to a new study. These phytoplankton create the energy that fuels ocean ecosystems, and the study found that half of this energy is produced under the sea ice in late winter and early spring, and the other half at the edge of the ice in spring.

CORAL REEFS CAN TAKE THE HEAT, UNLIKE EXPERTS CRYING WOLF

by Peter Ridd, December 26, 2018 in GWPF


Scientists from James Cook University have just published a paper on the bleaching and death of corals on the Great Barrier Reef and were surprised that the death rate was less than they expected, because of the adaptability of corals to changing temperatures.

It appears as though they exaggerated their original claims and are quietly backtracking.

To misquote Oscar Wilde, to exaggerate once is a misfortune, to do it twice looks careless, but to do it repeatedly looks like unforgivable systemic unreliability by some of our major science organisations.

The very rapid adaptation of corals to high temperatures is a well-known phenomenon; besides, if you heat corals in a given year, they tend to be less susceptible in the future to overheating. This is why corals are one of the least likely species to be affected by climate change, irrespective of whether you believe the climate is changing by natural fluctuations or because of human influence.

Corals have a unique way of dealing with changing temperature, by changing the microscopic plants that live inside them. These microscopic plants, called zooxanthellae, give the coral energy from the sun through photosynthesis in exchange for a comfortable home inside the coral. When the water gets hot, these little plants effectively become poisonous to the coral and the coral throws them out, which turns the coral white — that is, it bleaches.